A Raw format image refers to the unprocessed data from a digital image sensor.
Professional cameras (including DSLRs) usually have this as an output option, along with JPEG. Raw format images are superior to JPEG in terms of dynamic range, color depth, and fidelity, but are larger in filesize. The main weakness of the raw format is the lack of standard—raw format images typically cannot be viewed on a computer without installing an appropriate codec,whereas the JPEG codec is standard on every operating system. Photoshop must use the appropriate version of the Camera RAW utility to view raw images from certain cameras.
Adobe has developed its own format called Digital Negative, which uses the
.DNG extension. Certain cameras from manufacturers such as Casio, Leica, Pentax, Ricoh, and Samsung use DNG in lieu of an actual raw format.
Practical use of raw formatEdit
The raw format available to your camera should be the primary output type because the extra dynamic range and color depth allows for more strenuous editing without visible loss of quality. By definition, raw format also uses the camera's maximum image dimensions. Because raw images are the largest filesize generated by the camera, keep plenty of memory card storage on hand when shooting.
Remember the basic rule of editing: you can always take away, but you can never put back. Any image processing should be done in Photoshop, and in a specific order. Using the camera's JPEG format drastically limits the editing possibilities of an image. Saving to JPEG (or other image formats) should be the last step in the editing process.
File extensions by manufacturerEdit
Different camera manufacturers use different file extensions for their raw format images:
- Phase One
- Konica Minolta
Some other manufacturers use the
.RAW extension, which may unfortunately be mistaken for other "raw data files" from other sources.